Help on swing wing biplane glider

[BABAR]

The biplane wings are not going to have any dihedral. I am trying to figure out how to get roll stability. Will a dihedral on the tail work? Will a slight sweep on the wings help?

 

[kjohnson]

Sweeping the wings will give a dihedral -like roll stability benefit in a flat wing, but you need more than a slight sweep. Take a look at something like the Twinsee here https://www.unclemikesrocketshack.com/Edmonds.html where the sweep length is the same as the root chord.

kj

 

[BABAR]

Sweeping the wings will give a dihedral -like roll stability benefit in a flat wing, but you need more than a slight sweep. Take a look at something like the Twinsee here https://www.unclemikesrocketshack.com/Edmonds.html where the sweep length is the same as the root chord.

kj

Maybe i am asking the wrong question. The thing i am thinking about is how to get the glider into the original glide up-IS-UP and down-is-DOWN configuration. On the Twinsee (which I actually have) I am guessing that the nose and body tube "dangle" below the high wing and tail. On the biplane, the wings are rotated in launch position parallel to the body of the rocket, which has a square cross section so the*wings are held tightly to the body at launch to reduce drag. At deployment the upper wings are even with the top of the fuselage and the lower wings similarly are even with the bottom. So how does the glider "know" which way is up? Once it gets "ORIENTED" I agree the wing sweep will help keep it that way.

Would a boom tail like the Twinsee or a V-tail help achieve that initial upright orientation?

 

[JoeG]

Generally, wing sweep is not as effective in roll stability as dihedral is. I seem to remember something about one degree of dihedral being equal to about three degrees of sweep. Using sweep to control roll can work but is dependent upon angle of attack also. As you probably already know, gliders and flight in general, is a balancing act of many variables.

A lot of test gliding will be in order but i'kll bet you can do it.

 

[kjohnson]

Are you planning on a rear motor that ejects? What does your tail look like? You could have a movable elevator that is locked down for boost by the motor pod and then pops up (like the Sky Dart, SWT, Crusader, etc) and that will define top and bottom of the glider. Are you putting an airfoil in the wings? That will also orient the glider as you will have the same airfoil on the top and bottom wing (flat on the bottom, rounded on the top).

kj